1. Field of the Invention
The present invention relates to a magnetic detection device and a fabrication method thereof, and more particularly, to a magnetic detection device including a magnetic detection element, which detects an external magnetic field, and a detection circuit that detects an electrical resistance of the magnetic detection element.
2. Description of the Related Art
A magnetic detection device that detects an external magnetic field is used for a non-contact ON-OFF switch, a rotary encoder that detects a phase of rotation or the number of rotations, and the like. A known magnetic detection device mainly uses a hall element as a magnetic detection element. However, a magnetic detection device using a hall element has a disadvantage in that a circuit configuration of the detection circuit is complex because a correction circuit is necessary for a detection output. A magnetic detection element using a magneto-resistance effect has an advantage in that the circuit configuration of the detection circuit can be relatively simple and can detect the external magnetic field with high precision.
The invention related to a hybrid IC of which a magnetic conversion IC chip integrating the hall element, a magnetic conversion element, or the like and other circuit components disposed on a substrate is disclosed in a Patent Document 1 (Japanese Unexamined Patent Application Publication No. 8-279326).
Although it is described in the above-mentioned Patent Document 1 that the hall element, the magneto-resistance element, or the like is integrated in the magnetic conversion IC chip, its integrated structure is not clearly described. When the IC chip is fabricated by two-dimensionally arranging a circuit having a magnetic conversion element on a substrate, only the IC chip itself is relatively large. Additionally, because the hybrid IC described in the patent document 1 has the magnetic conversion IC chip and other circuit components two-dimensionally arranged on the same substrate, an area of an integrated circuit having the magnetic conversion element and a process circuit thereof becomes larger. Therefore, it is not appropriate to mount the integrated circuit on a small device. Also, even when it is mounted on something other than the small device, a space for disposing other component or a mechanism is limited because the space for forming the integrated circuit is required to be large.